Integrated circuits (IC) typically include numerous of microelectronic devices or dies formed on a single semiconductor wafer. Electrical connections between the wafer and external electrodes of a wafer package are typically made by bond wires and bond pads provided on the wafer.
For example, we have observed contamination, such as fluorine (F) contamination, on the surface of the bond pad, even with de-fluorination using oxygen/nitrogen/hydrogen positive photoresist stripper (O2/N2/H2 PRS), especially on wafers with deep trenches which form scribe lines for dicing the wafer. Fluorine contamination leads to unreliable bonds between the bond wire and bond pad. For example, F in the bond pad may lead to breakage of the bonds. In extreme cases, excessive F may make it difficult to even form a bond between a bond wire and a bond pad. As such, F contamination may cause bond failure and result in low yields.
The present disclosure is directed to reducing F contamination in bond pads to improve bond reliability.